This invention relates to an idler roll assembly for a conveyor belt and the method of producing the same and more particularly to improved means for securing an idler roll cylinder to roll heads mounted within the ends of the roll cylinder.
Heretofore in the art to which our invention relates, difficulties have been encountered in securing an idler roll cylinder to the roll heads mounted within the ends thereof due to the fact that the roll heads often become separated from the roll cylinder whereby the heads move axially to thus move deeper into the roll cylinder or move outwardly thereof. Also, with most prior art roll assemblies, the head has a tendency to rotate relative to the roll cylinder whereby the head spins or turns inside the roll cylinder to thus further increase wear therebetween.
One method heretofore employed to secure the roll heads to the roll cylinder has been to braze or weld the roll head to the roll cylinder, as shown in the Deems et al. U.S. Pat. No. 2,285,647 and the Kindig U.S. Pat. No. 2,702,868. With the brazed or welded type, the joint between the heads and the roll cylinder often does not extend the entire 360.degree. around the roll due to the fact that you only obtain a good braze joint where the flux has been properly applied. Furthermore, if the heads are not properly brazed to the cylinder, paint or water can leak through into inside of the roll assembly. Another difficulty with providing a brazed joint between the heads and the roll cylinder is that flux is left on the end of the brazed rolls, thus resulting in a rough appearance.
Another difficulty encountered with some prior art roll assemblies is the fact that the ends of the roll are not smooth but are provided with relatively sharp edges which often cut the conveyor belt or greatly increase the wear thereof. This type roll assembly is shown in the Brown U.S. Pat. No. 3,198,318.
With another type of prior art roll assembly, the roll cylinder is profiled or machined whereby it corresponds to the outer surface of the roll head inserted therein. Such a roll cylinder is shown in U.S. Pat. No. 3,774,282. Since the roll cylinder is profiled or machined it is thinner along the area of contact with the roll head. With such rolls, the thinner area often wears through, thus causing separation of the head from the roll cylinder and at the same time causing damage to the conveyor belt. Still another problem encountered with machining or profiling the inside diameter of the roll cylinder is that poor concentricity of the outer surface of the roll cylinder and the center line of the bearings is often obtained. That is, where the inside diameter of the roll cylinder is profiled, the concentricity of the roll cylinder varies as much as the diameter of the roll cylinder varies.